mirror of
https://git.sr.ht/~rabbits/uxn
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158 lines
6.5 KiB
C
158 lines
6.5 KiB
C
#include "uxn.h"
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/*
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Copyright (u) 2021 Devine Lu Linvega
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Copyright (u) 2021 Andrew Alderwick
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Permission to use, copy, modify, and distribute this software for any
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purpose with or without fee is hereby granted, provided that the above
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copyright notice and this permission notice appear in all copies.
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THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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WITH REGARD TO THIS SOFTWARE.
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*/
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#define MODE_SHORT 0x20
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#define MODE_RETURN 0x40
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#define MODE_KEEP 0x80
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#pragma mark - Operations
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/* clang-format off */
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/* Utilities */
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static void (*push)(Stack *s, Uint16 a);
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static Uint16 (*pop8)(Stack *s);
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static Uint16 (*pop)(Stack *s);
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static void (*poke)(Uint8 *m, Uint16 a, Uint16 b);
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static Uint16 (*peek)(Uint8 *m, Uint16 a);
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static void (*devw)(Device *d, Uint8 a, Uint16 b);
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static Uint16 (*devr)(Device *d, Uint8 a);
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static void (*warp)(Uxn *u, Uint16 a);
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static void (*pull)(Uxn *u);
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/* byte mode */
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static void push8(Stack *s, Uint16 a) { if(s->ptr == 0xff) { s->error = 2; return; } s->dat[s->ptr++] = a; }
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static Uint16 pop8k(Stack *s) { if(s->kptr == 0) { s->error = 1; return 0; } return s->dat[--s->kptr]; }
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static Uint16 pop8d(Stack *s) { if(s->ptr == 0) { s->error = 1; return 0; } return s->dat[--s->ptr]; }
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static void poke8(Uint8 *m, Uint16 a, Uint16 b) { m[a] = b; }
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static Uint16 peek8(Uint8 *m, Uint16 a) { return m[a]; }
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static void devw8(Device *d, Uint8 a, Uint16 b) { d->dat[a & 0xf] = b; d->deo(d, a & 0x0f); }
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static Uint16 devr8(Device *d, Uint8 a) { return d->dei(d, a & 0x0f); }
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static void warp8(Uxn *u, Uint16 a){ u->ram.ptr += (Sint8)a; }
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static void pull8(Uxn *u){ push8(u->src, peek8(u->ram.dat, u->ram.ptr++)); }
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/* short mode */
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static void push16(Stack *s, Uint16 a) { push8(s, a >> 8); push8(s, a); }
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static Uint16 pop16(Stack *s) { Uint8 a = pop8(s), b = pop8(s); return a + (b << 8); }
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void poke16(Uint8 *m, Uint16 a, Uint16 b) { poke8(m, a, b >> 8); poke8(m, a + 1, b); }
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Uint16 peek16(Uint8 *m, Uint16 a) { return (peek8(m, a) << 8) + peek8(m, a + 1); }
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static void devw16(Device *d, Uint8 a, Uint16 b) { devw8(d, a, b >> 8); devw8(d, a + 1, b); }
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static Uint16 devr16(Device *d, Uint8 a) { return (devr8(d, a) << 8) + devr8(d, a + 1); }
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static void warp16(Uxn *u, Uint16 a){ u->ram.ptr = a; }
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static void pull16(Uxn *u){ push16(u->src, peek16(u->ram.dat, u->ram.ptr++)); u->ram.ptr++; }
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#pragma mark - Core
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int
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uxn_eval(Uxn *u, Uint16 vec)
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{
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Uint8 instr;
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Uint16 a,b,c;
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if(!vec || u->dev[0].dat[0xf])
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return 0;
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u->ram.ptr = vec;
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if(u->wst.ptr > 0xf8) u->wst.ptr = 0xf8;
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while((instr = u->ram.dat[u->ram.ptr++])) {
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/* Return Mode */
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if(instr & MODE_RETURN) {
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u->src = &u->rst;
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u->dst = &u->wst;
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} else {
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u->src = &u->wst;
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u->dst = &u->rst;
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}
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/* Keep Mode */
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if(instr & MODE_KEEP) {
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pop8 = pop8k;
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u->src->kptr = u->src->ptr;
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} else {
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pop8 = pop8d;
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}
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/* Short Mode */
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if(instr & MODE_SHORT) {
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push = push16; pop = pop16;
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poke = poke16; peek = peek16;
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devw = devw16; devr = devr16;
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warp = warp16; pull = pull16;
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} else {
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push = push8; pop = pop8;
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poke = poke8; peek = peek8;
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devw = devw8; devr = devr8;
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warp = warp8; pull = pull8;
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}
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switch(instr & 0x1f){
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/* Stack */
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case 0x00: /* LIT */ pull(u); break;
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case 0x01: /* INC */ a = pop(u->src); push(u->src, a + 1); break;
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case 0x02: /* POP */ pop(u->src); break;
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case 0x03: /* DUP */ a = pop(u->src); push(u->src, a); push(u->src, a); break;
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case 0x04: /* NIP */ a = pop(u->src); pop(u->src); push(u->src, a); break;
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case 0x05: /* SWP */ a = pop(u->src), b = pop(u->src); push(u->src, a); push(u->src, b); break;
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case 0x06: /* OVR */ a = pop(u->src), b = pop(u->src); push(u->src, b); push(u->src, a); push(u->src, b); break;
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case 0x07: /* ROT */ a = pop(u->src), b = pop(u->src), c = pop(u->src); push(u->src, b); push(u->src, a); push(u->src, c); break;
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/* Logic */
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case 0x08: /* EQU */ a = pop(u->src), b = pop(u->src); push8(u->src, b == a); break;
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case 0x09: /* NEQ */ a = pop(u->src), b = pop(u->src); push8(u->src, b != a); break;
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case 0x0a: /* GTH */ a = pop(u->src), b = pop(u->src); push8(u->src, b > a); break;
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case 0x0b: /* LTH */ a = pop(u->src), b = pop(u->src); push8(u->src, b < a); break;
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case 0x0c: /* JMP */ a = pop(u->src); warp(u, a); break;
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case 0x0d: /* JCN */ a = pop(u->src); if(pop8(u->src)) warp(u, a); break;
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case 0x0e: /* JSR */ a = pop(u->src); push16(u->dst, u->ram.ptr); warp(u, a); break;
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case 0x0f: /* STH */ a = pop(u->src); push(u->dst, a); break;
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/* Memory */
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case 0x10: /* LDZ */ a = pop8(u->src); push(u->src, peek(u->ram.dat, a)); break;
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case 0x11: /* STZ */ a = pop8(u->src); b = pop(u->src); poke(u->ram.dat, a, b); break;
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case 0x12: /* LDR */ a = pop8(u->src); push(u->src, peek(u->ram.dat, u->ram.ptr + (Sint8)a)); break;
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case 0x13: /* STR */ a = pop8(u->src); b = pop(u->src); poke(u->ram.dat, u->ram.ptr + (Sint8)a, b); break;
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case 0x14: /* LDA */ a = pop16(u->src); push(u->src, peek(u->ram.dat, a)); break;
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case 0x15: /* STA */ a = pop16(u->src); b = pop(u->src); poke(u->ram.dat, a, b); break;
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case 0x16: /* DEI */ a = pop8(u->src); push(u->src, devr(&u->dev[a >> 4], a)); break;
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case 0x17: /* DEO */ a = pop8(u->src); b = pop(u->src); devw(&u->dev[a >> 4], a, b); break;
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/* Arithmetic */
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case 0x18: /* ADD */ a = pop(u->src), b = pop(u->src); push(u->src, b + a); break;
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case 0x19: /* SUB */ a = pop(u->src), b = pop(u->src); push(u->src, b - a); break;
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case 0x1a: /* MUL */ a = pop(u->src), b = pop(u->src); push(u->src, b * a); break;
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case 0x1b: /* DIV */ a = pop(u->src), b = pop(u->src); if(a == 0) { u->src->error = 3; a = 1; } push(u->src, b / a); break;
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case 0x1c: /* AND */ a = pop(u->src), b = pop(u->src); push(u->src, b & a); break;
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case 0x1d: /* ORA */ a = pop(u->src), b = pop(u->src); push(u->src, b | a); break;
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case 0x1e: /* EOR */ a = pop(u->src), b = pop(u->src); push(u->src, b ^ a); break;
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case 0x1f: /* SFT */ a = pop8(u->src), b = pop(u->src); push(u->src, b >> (a & 0x0f) << ((a & 0xf0) >> 4)); break;
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}
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if(u->wst.error) return uxn_halt(u, u->wst.error, "Working-stack", instr);
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if(u->rst.error) return uxn_halt(u, u->rst.error, "Return-stack", instr);
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}
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return 1;
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}
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/* clang-format on */
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int
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uxn_boot(Uxn *u)
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{
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unsigned int i;
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char *cptr = (char *)u;
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for(i = 0; i < sizeof(*u); i++)
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cptr[i] = 0x00;
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return 1;
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}
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Device *
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uxn_port(Uxn *u, Uint8 id, Uint8 (*deifn)(Device *d, Uint8 port), void (*deofn)(Device *d, Uint8 port))
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{
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Device *d = &u->dev[id];
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d->addr = id * 0x10;
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d->u = u;
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d->mem = u->ram.dat;
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d->dei = deifn;
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d->deo = deofn;
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return d;
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}
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